Display screen or portion thereof with an animated graphical user interface



FIG. 1 is a first image in a sequence for a display screen or portion thereof with an animated graphical user interface showing our new design;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof; and,

FIG. 5 is a fifth image thereof.

The appearance of the graphical user interface transitions sequentially between the images shown in FIGS. 1-5. The process or period in which one image transitions to another forms no part of the claimed design. The broken lines showing a display screen and the other broken lines showing elements of the graphical user interface illustrate portions of the article and do not form part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with an animated graphical user interface, as shown and described. 